Upon the completion of the Human Genome Project, the entire base sequence of the human genome became known and numerous genes are being disclosed along with their functions. Detection of individual gene mutation or abnormality has therefore become increasingly important as it will contribute to the development of so-called post-genome medicine, therapy, diagnosis and the like. For example, it is expected that the detection of a single nucleotide polymorphism (SNP) in humans will provide basic information for tailor-made medical services or personalized medicine adapted individual differences.
Recently, the need has also intensified for DNA analysis aimed at inhibiting and preventing false representation of food products so that there can be secured agricultural products, marine products, livestock products and the like which are safe and meet consumer demand.
Gene detection is also useful as a measure to determine if a microorganism present in the ground, water or atmosphere is harmful or detoxicated, due to natural or unnatural environmental variation: It is important to know the alteration of the microorganism, for example, whether or not the microorganism has a specific base which is involved in making it harmful.
Techniques primarily employed hitherto for gene detection for the above-mentioned purposes include amplification of a target gene by RCR reaction, followed by analysis of the gene by direct sequencing or capillary electrophoresis to determine the presence of mutation. A real-time PCR reaction method is also known in which a DNA probe is used to monitor the RCR reaction so that a target gene is quantified for the analysis of polymorphism or mutation [For example, Japanese Patent Application Publication No.2002-275 (Patent Reference 1), Japanese Patent Application Publication No.2002-119291 (Patent Reference 2)].
However, these conventional methods have a drawback that only a limited amount of DNA is obtained by the RCR reaction and, a high level of knowledge and skill are needed for obtaining reproducible and reliable results. Shortcomings are also found in that there are needed costly analytical devices such as a DNA sequencer and that a long time is required for analysis. If electrophoresis is employed, more time and effort will be needed for analysis.
Patent Reference 1: Japanese Patent Application No.2002-275
Patent Reference 2: Japanese Patent Application No.2002-119291